I'll put down a firm, "No idea." Compared to two years ago, many schools have moved much of the process online. I think that many of them will contact candidates by email on March 10th. I could be wrong. There's always the fear of making enormous mistakes by email: Oops! UC San Diego Mistakenly Sends Acceptance E-mails to Thousands - Campus Chatter
Some schools in the past have gone to the effort to delay emails until after 3 pm or so. As a parent I appreciate this. Some applicants seem to be able to talk their parents into staying home from school on March 10th, which seems to show a lack of respect for the current school. Others seem to check their emails while at school, which must lead to a great deal of in-school drama between the admitted and the not admitted.
In my opinion, it would be a good idea to email candidates either at 12:01 a.m., or after 3 p.m. on March 10th. It would have the added benefit of relieving me of the temptation of peeking!